Flue-tube superheater.



Patented Sept. 26, 1916.

2 SHEETS-SHEET I I INVENTOR G/ ITUT E. M/LLE/f WITNESSES.

G. E. MILLER.

FLUE TUBE SUPERHEATEh.

APPLICATION FILED SEPT. 14 1915.

1 1 99,405 Patented Sept. 26, 1916.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

GARRETT E. MILLER, OF WEST NYACK, NEW YORK, ASSIGNOR TO LOCOMOTIVE $UPER- HEATER COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

FLUE-TUBE SUPERHEATER.

To all whom it may concern Be it known that I, GARRETT E. MILLER, a citizen of the United States, residing at Vest Nyack, Rockland county, State of New York, have invented certain new and useful Improvements in Flue-Tube Superheaters, of which the following is a specification. 1

My invention relates to superheaters of the type employing tubes inserted in some or all of the flue tubes of a flue tube boiler, said tubes being connected at their ends to suitable main pipes or collecting chambers in such a way that saturated steam passes from the boiler through the tubes, where it is superheated, to the steam chests of the engine. The flue tubes employed to hold the superheater may be of normal size or may be enlarged, as the case may be. superheaters of this type are largely used for locomotive and marine work and also find considerable application in stationary boiler and engine practice.

It is the object of my present invention to provide a superheater, of the class referred to, with a novel arrangement of collecting headers with reference to which the superheater tubes or elements may be attached or detached conveniently, quickly and easily.

A further object of my invention is to provide such an arrangement of headers and superheater elements as will require but a single shape of superheater' element so that any element may be placed in any flue tube;

This makes for speedy manufacture and economical construction as Well as for economy in ,repairs, inasmuch as but one style of superheater element need be carried in stock.

A further object of my invention is to rovide an arrangement of superheater lieaders in which the unequal expansion of the saturated and superheated .headers, due to the diverse temperatures ofthe contained saturated and superheated steam and the unequal expansion of the superlieater collectors and elements as compared with that of the boiler shell from which said parts are supported, shall not exert any injurious strains upon the header structure.

Still a further object of my invention is to provide a novel form of element end and associated clamping arrangement by means of which the elements may be quickly attached toand detached from the headers and the joints between headers and element Specification of Letters Patent.

Patented Sept. 26, 1916.

Application filed September 14, 1915. Serial No. 50,568.

ends may be made steam tight and maintained tight despite the jars of operation and the strains induced by changing temperatures.

Other objects of myinvention will appear as the specification proceeds. I

My invention will be better understood by referring to the accompanying drawings in whicha Figure 1 represents a central sectional elevation (along the line 1-1 of Fig. 2) through the smoke box end of a locomotive boiler provided with a superheater'faccording to my invention; Fig. 2 represents a view taken from the right of Fig. 1 ;Fig. 3 represents a section, enlarged, taken along the line 33 of Fig. 1; and Fig. 4 represents a section along the same line as Fig. 3, but still further enlarged, so as to show the detailed construction of the element ends and of the clamping means which attaches them to the header branches.

In the. drawings, the boiler, 1, having the usual front tube sheet, 2, the normaldiametered fiue tubes, 3, and enlargedflue tubes, 4, is further provided with a header, 5, arranged in the smoke box, 6, in front of the flue tubes. This header comprises a pair of transverse collecting chambers, 7, and, 8, for saturated and superheated steam respectively, extending across the boiler above the smoke tubes. The saturated chamber, 7, is supplied with steam through a bent inlet pipe, 9, which is connected, in the usual way,

at the front tube sheet to apipe, 10, leading from the steam dome ofthe boiler. Similarly the superheated steam chamber, 8, is provided with a pair of laterally disposed pipe connections, 11, 11, to which are joined pipes, 12, leading to the two steam chests (not shown). The two collecting chambers, 7, and, 8, with their inlet and outlet pipes, 9, and, 11, constitute, with the header branches now to be described, an'integral one piece structure.

Opening from the collecting chambers, 7, and, 8, and extending vertically downward between alternate vertical rows of enlarged flue tubes are header branches, 13, and, 14, for saturated and superheated steam respectively. These branches are preferably parallel sided and have smaller dimensions, taken across the boiler than in the length of the boiler; they are arranged in pairs with the superheated branches in front of the saturated branches. Each superheated and saturated header of a pair is connected together, at a point just above the top row of ue tubes but below the collecting chambers by a solid yoke, 15. 1

There is one superheated element, 16, to

each enlarged smoke tube; this element com- I prises four tube lengths laid side by side and joined in series by return bends in the usual way. The free ends, 17 and, 18, of each element are brought out one above the other and bent slightly toward the axis of the flue tube as they emerge therefrom. One of the ends is left substantially-straight,

while the other and longer end is bent- .0 the head, 19, is provided with a spherically tipped boss or projection, 20. 7 J A single clamp is used for attaching both ends of a single element to the two headers.

This clamp comprises a linear bar, 21, having a central opening through which is inserted a bolt, 21, which is also inserted through the space between the front and rear headers of a pairand the head,'22, of-

which is locked in recesses provided by lugs, 23, formed upon the sides of the headers, whereby the bolt is prevented from turning. Each end of the clamp is provided with a recess in which is seated the boss, 20, of the head ,19. Nuts, 24, threaded upon the end i of the bolt, force the spherically formed sides of the heads into steam tight engagement with the similarly formed openings of the headers.

As previously stated, the shape of each element is like that of every other element. Those elements belonging to the flue tube which lies immediately to the left of a pair .of header branches (as viewed from Fig. 2)

' have their longer ends below the center of the flue tube and extending downwardly from rear to front; the clamp bar, 21, there'- fore, also extends downwardly from rear to front Those elements belonging to the flue tubes immediately to the right of any pair of header branches are reversed, with respect to the elements to the left as just described, a. 6., the elements are rotated axially through 180. The longer ,ends of each element,

therefore, are now above the center of-the .fiue tube and are bent forwardly and upwardl'y and the clamp members similarly extend upwardly from rear to front. It will be-seen that the above arrangement brings the two bolts, 21, belonging to the two elements at the right and left of a header branch, one above the other so that neither interferes with the other but is quite independent thereof. Any individual element may, therefore, be removed and repaired or replaced at any time without disturbing any other element.

Both the collecting chambers, 7, 8, and header branches 13,14, being spaced away from one another and there being no physical connection between the saturated system (collecting chamber, 7, and header branches,

13,) and the superheated system (collecting chamber and header branches 14:) except that of the narrow sectional yoke, 15, there is but little loss of heat from the superheated to the saturated system, and, for the same reason, the parts of the saturated system, and of the superheated system, which are at different temperatures, are free to expand and contract independently and no injurious strains are set up in the header structure because of' said diiferenttemperatures. Furthermore, by. reason of the yoke, 15, being below the collecting chambers but above the flue tubes, the two collecting chambers as well as the members of each pair of header branches may be displaced, through reasonable limits, with reference to one another, 'the yoke, 15, serving as a pivotal axis for such displacement. Forces tending to sodisplace the collecting chambers arise not only by reason of the temperature differences between saturated and superheated steam but also because of the fact that the outlet pipes, 11, which are rigidly joined to the superheated collecting chamber, are supported from a part of the boiler mounting which remains much cooler than the collecting chambers themselves or than the inlet pipe, 9, joined to the saturated collecting chamber. And forces tending to so displace the header branches arise because of the fact that each superheated element end assumes a much higher temperature than the corresponding saturated end so that the header branches are forced apart for increased production of superheated steam and drawn together for decreased production of superheated steam.

Y The flue tubes which contain superheater elements, being at the sides of the header branches, are very accessible for cleaning, and the clamps and element ends being directly in front of the flue tubes, any superheater element may be drawn straight forward for repair or replacement and will not be interfered withlby any other element or by any part of the header structure;

In special cases the'header structure ma be strengthened by joining a detachable-lin between the lower portions of the several pairs (saturated and superheated) of header branches.

These links should be so attached that each branch is free to shorten or lengthen vertically without transmitting strain to the link or to the other branch.

Having described my invention, I claim: In a flue tube boiler provided with a superheater header having pairsof superheated and saturated header branches, one in front of and spaced from the other, between alternate vertical rows of flue tubes, said branches having lateral openings, superheater elements in some of the flue tubes, heads on the ends of each element each head having a spherically shaped side and an openingtherethrough and on opposite side having a spherically tipped boss, the open ings of a pair of ends being in registry with openings in a pair of header branches, a clamp bar having end recesses to receive the spherically tipped bosses,'and a bolt passing between the branches and through the center of the clamp bar for holding the element ends fast.

In testimony whereof I have hereunto set my hand.

GARRETT E. MILLER. 

